Bellows restraining device



Nov. 2l, 1967 J. F. PEYTON BELLows RESTRAININGDEVICE Filed Oct. 18. 1965 INVENTOR. c/H/s/ /1- PES/70N MMM United States Patent O 3,353,846 BELLOWS RESTRAININ G DEVICE John F. Peyton, Long Beach, Calif., assignor to Federal Mogul Corporation, Detroit, Mich., a corporation of Michigan Filed Oct. 18, 1965, Ser. No. 497,012 8 Claims. (Cl. 285-16) ABSTRACT F THE DISCLOSURE A device for use in internally restraining a conduit bellows that comprises an interlaced pair of swivelly engaged fiat plate struts of a geometry permitting disengagement of the swivel means, and a process of fabricating same.

The present invention relates to bellows units for conduits and, particularly, to an internal restraining and reinforcing device for bellows units to accommodate expansion, contraction, bending and twisting in tubular conduits.

The present invention is an improvement over the restraining device of the bellows unit disclosed in my prior Patent No. 3,070,387 and provides an internal structure that is made up of an assembly of fewer parts of less weight, and thus further enhances the use of the device in airborne applications. The present invention further minimizes the cross-sectional area of the restraining means so as to further minimize pressure drops in the fluid passing through the conduit in which the bellows unit is disposed. Additionally, the present unit can be fabricated with fewer steps in the manufacturing process and by a process that eliminates certain welding steps after heat treatment inherent in the manufacture of the prior device so that the completed product more nearly conforms -to the desired hardness and toughness characteristics induced by the heat-treating step.

These and other objects and advantagse of the invention will be apparent from the following description, when taken in connection with the annexed drawing in which:

FIGURE 1 is an elevational view, partly in section, of an internally reinforced bellows unit incorporating the improved reinforcement means of this invention;

FIGURE 2 is a perspective view of the presently preferred embodiment of the reinforcing means of FIG- URE l;

FIGURE 3 is a perspective view of the same parts as are shown in FIGURE 2, but with the parts differently oriented to illustrate a step in the manufacturing process; FIGURE 4 is a fragmentary plan view of an alternative embodiment of the invention; and

FIGURE 5 is a perspective view of the reinforcing means of FIGURE 4, with the parts oriented out of operational alignment to illustrate a step in the manufacturing process.

The preferred embodiment of the invention, as best seen in FIGURE 2, comprises a pair of interlaced strut assemblies and 10 that are identical to one another but differently numbered for convenience of identificatoin. Both of these are swivelly engageable on a ball 11 contained between confronting seat portions formed in the strut assemblies. The interlaced strut assemblies 10, 10 and ball 11 comprise the reinforcing means for a completed bellows unit, such as is shown in FIGURE 1. The completed unit includes a pair of short tubes 12 and 13 that are interconnected by the interlaced strut assemblies 10, 10 internally, and that are externally interconnected by a short length of metallic bellows 14.

3,353,846 Patented Nov. 2l, 1967 ICC Each of the tubes 12 and 13 externally mounts an adaptor collar 15, welded thereto, to which one end of the metallic bellows 14 is connected by welding. It will, of course, be understood that the completed bellows unit is employed to interconnect confronting ends of a pair of conduits, and functions to accommodate axial contraction and expansion of the conduit means, as well as bending and twisting, within fixed limits determined by the amount of play in the interlaced strut assemblies 10, 10 and ball 11.

More particularly, each strut assembly 10 and 10 is made up of a strut member 16 and a nose piece 17. The strut 16 has a base edge 18 of approximately the same length as the internal diameter of the tube 12 or 13 within which the restraining device is to be mounted, preferably such that opposite outer edges 19 of the strut 16 will be received in a close t for welding against diametrically opposite portions of the tube. A pair of angularly related edges 20 of the strut 16 extend symmetrically from the outer edges 19 toward an apex of the strut, to merge into short diametrically disposed edges 21.

Each strut 16 is formed with a slot 22 disposed along the axis of symmetry of the piece and opening into the apex of the generally triangular portion of the piece. This slot has a relatively wide rear or closed end at a base edge 23, whose opposite ends merge into opposite sides 24 of the slot that symmetrically converge forwardly toward the apex of the pieoe. Each of the nose pieces 17 is of frusto-conical configuration, of a taper corresponding to the convergence or angle included between the opposite sides 24 of the slot 22, and is secured by rod welds 25 within the slot 22 to close the forward end of the slot, the nose of the nose piece 17 being disposed flush with the edges 21 at the apex of the strut 16. Each of the nose pieces 17, at its base, is formed with a concave ball seat 26, in which seats the ball 11 is received in the completed assembly of the restraining means.

The pair of strut assemblies .are mounted within the bellows unit to assume mutually perpendicular planes, as shown in FIGURE 1. Thus, one of the strut assemblies 10 is afiixed in one of the tubes 12 by welds 30 along the outer edges 19 of the strut 16, while the other strut assembly 10 is axed in the same manner Within the other tube 13, but approximately at right angles to the first strut `assembly lil. Then, when the conduit in which the bellows unit is mounted is under tension, the parts assume the relative positions shown in FIGURE l, in

which both nose pieces 17 are swivelly seated on the ball 11, leaving a small clearance space 31 between the -apex of each nose piece 17 and the adjacent base edge 23 of the opposite or other strut assembly. When the conduit is under compression, the nose pieces 17 will separate slightly Within the limits allowed by abutment of the apex of each nose piece 17 on the confronting base edge 23 of the other strut assembly. Thus, the nose pieces 17 cannot separate suiiciently to allow escape of the ball 11. In bending of the conduit, the tubes 12 and 13 can -be displaced angularly within the limits imposed Iby contact of a nose piece 17 with an edge 24 of the slot 22 of the other nose piece assembly.

For the device to operate successfully, it is essential that it provide the limits just described on bending, compression and expansion. However, for purposes of manufacture of the device, it is desirable to provide a means whereby the ball and socket means can be disengaged suiciently to remove the ball 11 after the interlaced assembly has been heat treated, in order to replace the old ball with a new ball 11. Further, this should be accomplished without per-forming any additional welding to `assemfble the interlaced struts, which would produce local discontinuities in the desired toughness and hardness 3 characteristics that had already been introduced by the heat treatment.

The configuration of parts employed meets both the operating conditions .and the assembly conditions of the device. Thus, once the device is installed in a bellows unit, it permits contraction, expansion and bending of the bellows without any danger of loss of the ball 11, within the positive limits desired. On the other hand, for pur poses of manufacture, the configuration of the parts permits a sequence of assembly whereby no welding operations are required ,after heat treatment and, further, permits a ball 11 to be removed from or placed into the assembly' at will.

Ths sequence of assembly is as follows:

Referring to FIGURE 2, the nose piece 17 of the strut assembly is first Welded into place on its strut 16. Then, the remaining strut member 16 for the assembly 10 can be interlaced with the first strut assembly 10 by disposing the remaining strut substantially `at right angles to the strut assembly 10 so that the thickness of the strut member 16 of the strut assembly 10 can be received in the slot 22 of the remaining strut member. Then, when the apex portion of the remaining strut 16 is disposed in the wider end of the slot 22 of the other strut assembly, the remaining strut 16 can be turned about an axis normal to its plane and moved bodily to displace its apex from the plane of the other strut assembly 10. The remaining nose piece 17 can then be welded into place, the relative positions of the parts now corresponding to what is shown in FIGURE 3. In that figure, it will be observed that a major portion of the length of the slot 22 of the strut assembly 1t) is entirely clear of the plane of the other strut assembly 10'.

Now, a temporary ball 11 is disposed in one of the seats 26, after which the two strut assemblies are manipulated to bring the two nose pieces 17 into alignment. In this connection, the narrowness of the apex of the nose pieces 17 relative to the width of the slot 22 at their blind ends provides sufficient' clearance at corners 23a of the slot 22 to allow the nose piece y17 to be swung into .and out of the plane of the opposite strut assembly. The interlaced strut assemblies 10 `and 10 and dummy ball 11 are then heat-treated, the dummy ball serving to keep the seats 26`clean.

In FIGURE 2, three mutually perpendicular and intersecting axes X, Y .and Z are shown, about which the parts can swivel on the ball 11, to further illustrate the manner in which the parts can be moved, relative to one another, to remove and replace the ball 11, notwithstanding the positive limits to the swivelling action about al1 axis which the parts provide. Thus, .assuming the strut assembly 10' is held stationary, if the assembly 10 is moved about the Z and Y axes, simultaneously or in sequence, to the limit imposed by contact of the nose pieces 17 with -the side edges 24 of the slots 22, the apex of the nose piece 17 will be disposed at a clearance corner 23a of the assembly 10' and point to one side of the plane of that strut assembly. At the same time, the base edge 23 of the assembly 10 will swing away from in front of the nose piece 17 of the assembly 10' and will then be opposite one of the tapered edges of the assembly 10'. Now, the assembly 10 can be moved bodily or translated to move its nose piece away from the ball seat of the other nose piece and so arrive `at the position illustreated in FIGURE 3.

FIGURES 4 and 5 show an alternative embodiment of the invention. In this case, the restraining and reinforcing device comprises one of the previously described strut assemblies 10, and another strut assembly 10a. In this embodiment, there is no separate ball element, the assembly 10a instead incorporating a nose piece 17a which has an integral hemispherical portion 34 that seats on the ball seat 26 of the strut assembly 10. In all other respects, the alternative embodiment of the invention is identical to that previously described.

The alternative embodiment of the invention is assembled in substantially the same manner as the preferred embodiment, but can be made without the use of any counterpart of the dummy ball used in the heat-treatment of the preferred embodiment. Thus, the strut assembly 10a is first put together by welding the nose piece 17a into the slot 22 at the apex of the strut member 16. The strut 16 of the strut assembly 10 can then be interlaced with the completed assembly 16a and the apex portion thereof displaced from the plane of the assembly 16a in the manner shown in FIGURE 5. The then empty open end of the slot 22 is then clear for welding the nose piece 17 to the strut member 16 of the assembly It) with welds 25. The two assemblies can then be. turned relative to one another to dispose the two nose pieces 17 and 17a in a common plane by virtue of the clearance corners 23a of the two assemblies, but before this is done, a protective compound is applied to the ball seat 26 and the hernispherical projection 34 to protect these surfaces during heat-treatment. After heat-treatment, the two assemblies can again be returned to the offset positions of FIGURE 5, after which the protective compound may be removed. With the parts remaining in the offset positions of FIG- URE 5, there is clearance for a lapping tool to be inserted to clean of the ball seat 26 and projection 34 after which the two assemblies are returned to the coaxially aligned positions of the nose pieces 17 and 17a and the interlaced members then welded into place in tubes 12 and 13.

Variations in the foregoing embodiments and processes of my invention will undoubtedly occur to those skilled in the art. Accordingly, it is to be understood'that I do not wish to be limited to the exact details of construction and procedures set forth above, but only by the spirit and scope of the following claims.

I claim:

1. In a bellows restraining device of the type having a pair of interlaced strut assemblies with nose pieces .1ncluding a ball and socket means swivelly interconnecting said assemblies when under tension, a means for disengaging said ball and socket means comprising:

a flat plate in each of said strut assemblies, each of said plates having a pair of angularly related edges converging towards a nose piece and symmetrically disposed about an axis on opposite sides of a substantially triangular slot formed in said plate andV having symmetrically disposed about said axis,

confronting surfaces, including each of said nose pieces and edges of said slots of said plates, having first portions to positively limit separating movement of said nose pieces within two perpendicular planes intersecting the center of said ball and socket means and adapted to limit such separatin-g movement sufficiently to maintain said ball and socket means in self-centering operative association for reseating upon tensioning of said assemblies; second portions of said confronting surfaces positively limiting pivotal movement of each of said assemblies about a pair of perpendicular axes intersecting the center of said ball and socket means and lying in said perpendicular planes;

each of said assemblies being pivotal about both said axes to move a nose piece of one of said assemblies into a corner of the slot of the other of said assemblies, one of the angularly related edges of the plate of said one assembly then providing clearance with the corner of said slot of the other assembly to move said first portions out of opposing registration to permit further separating movement of said nose pieces sumciently to displace said ball and socket means out of said self-centering operative association and to allow access to substantially all surfaces of said ball and socket means.

2. A device as set forth in claim 1 in which said ball and socket means comprises a separate ball and a pair of concave ball seats, said ball seats being formed in confronting ends .of said nos@ pieces..

3. A device as set forth in claim 1 in which said ball and socket means comprises confronting end portions of said pair of nose pieces, one of said end portions bein-g formed with a concave ball seat and the other of said end portions being formed with a hemispherical projection.

4. A bellows restraining device with a disengageable swivel connection comprising:

a pair of strut assemblies and a ball and socket means, each of said strut assemblies comprising a flat plate having a pair of angularly related edges defining a generally triangularly shaped portion of said plate, said edges being symmetrically disposed on opposite sides of a slot formed in said plate, said slot opening forwardly at one end into an apex of said triangular portion, said slot having a base edge deinin-g a closed end of said slot and an opposite pair of side edges converging forwardly from corners at said base edge to said one end of said slot, said open end of said slot being at Ileast large enough to admit the thickness of one of said plates into said slot, each of said strut assemblies including a rigidly mounted nose piece of truncated frusto-conical configuration of a taper to matingly occupy the forward end of said slot with the axis of said nose piece on the axis of symmetry of said plate and with a larger base end of said nose piece facing rearwardly of said slot, said pair of strut assemblies being interlaced with the nose piece of one assembly disposed in the slot of the other assembly and behind the nose piece of the other assembly, said ball and socket means including the confronting base ends of said nose pieces and being adapted for swivelly interconnecting said strut assemblies upon tensioning of said interlaced strut assemblies, the nose piece of each assembly and the adjacent base edge being adapted for contact to limit axially opposed movement of said assemblies sufficiently to retain said ball and socket means in operative alignment so long as the axis of either of said nose pieces lies substantially in the plane of the adjacent one of said base edges, the nose piece of each assembly and the adjacent opposite pair of slot edges being adapted to limit pivotal movement about an axis normal to the .plane of said slot, the nose piece of each assembly and the base and opposite edges of the adjacent slot being adapted to permit axial separation of said nose pieces only after pivotal movement of one of said assemblies about both of a pair of perpendicular axes disposed within the plane of the other assembly, and the length of each of said base edges of said slots and the angle of the edges of each of said plates being so related and sized that when a nose piece of one assembly is moved into a corner of the slot of the other of said assemblies one of the angularly related edges of the plate of said one assembly provides clearance with said corner of said slot of the other assembly for access to said ball and socket means. 5. A bellows restraining device as in claim 1 in which said ball and socket means comprises:

a separate ball; each of said nose pieces at its base end being formed with a concave ball seat. 6. In the process of making a bellows restraining device, the steps comprising:

forming each of a pair of flat plate members with a pair of angularly related edges defining a generally triangular portion;

forming, in each of said members, a slot on the axis of symmetry of said triangular portion and opening into the apex of said portion, the slot being at least wide enough at said apex to receive the thickness of one of said members, said slot being formed symmetrically to have an angularly related pair of opposite side edges that converge forwardly from rear corners of the slot to the apex of said triangular portion;

forming a frusto-conically shaped pair of nose pieces with a taper conforming to the angle included between said slot edges and of a length less than onehalf the length of said slot;

symmetrically and rigidly securing one of said nose pieces into the forward end of the slot of one of said members to ll less than one-half the length of said slot to make a strut assembly of said one nose piece and said one member;

passing the thickness of the member of said s trut assembly into the slot of the remaining member, at a position offset from the nose piece of said strut assembly, to dispose the apex of said remaining member within the wider end of the slot of said assembly and then turning said remaining member, one of the angularly related edges of said remaining member then providing clearance with a corner of said slot of said assembly, to displace at least one-half the length of its slot out of the plane of the member of said assembly;

and rigidly and symmetrically securing the remaining one of said nose pieces into the forward end of the slot of the remaining one of said members to lill less than one-half the length of said slot to make a second strut assembly of said remaining nose piece and said remaining member, whereby said strut assemblies are permanently interlaced.

7. The process of claim 6 further characterized by the step of forming each of said pair of nose pieces with a concave seat in their larger ends and, after said strut assemblies are interlaced, placing a ball in the seat of one of said strut assemblies and moving at least one of said assemblies to dispose both of said nose pieces in a substantially common plane that includes at least one of said members whereby to retain said ball between said seats.

8. The process of claim 7 further characterized by subsequently heat treating said strut assemblies and ball, moving at least one of said assemblies to displace one of said nose pieces out of the plane of the member of the other strut assembly and out of contact with said ball, removing said ball and replacing it with a new ball and returning said assemblies to positions disposing both of said nose pieces in a substantially common plane including at least one of said members to retain said new ball between said seats.

References Cited UNITED STATES PATENTS 3,070,387 12/ 1962 Peyton 285-114 FOREIGN PATENTS 564,963 10/ 1944 Great Britain.

OTHER REFERENCES Daniels, C. M., et al. Pressure Loss for Internally Linked Bellows Joints, Sept. 14, 1961, pp. 187-189, Machine Design.

CARL W. TOMLIN, Primary Examiner.

RICHARD G. BERKLEY, Assistant Examiner. 

1. IN A BELLOWS RESTRAINING DEVICE OF THE TYPE HAVING A PAIR OF INTERLACED STRUT ASSEMBLIES WITH NOSE PIECES INCLUDING A BALL AND SOCKET MEANS SWIVELLY INTERCONNECTING SAID ASSEMBLIES WHEN UNDER TENSION, A MEANS FOR DISENGAGING SAID BALL AND SOCKET MEANS COMPRISING: A FLAT PLATE IN EACH OF SAID STRUT ASSEMBLIES, EACH OF SAID PLATES HAVING A PAIR OF ANGULARLY RELATED EDGES CONVERGING TOWARDS A NOSE PIECE AND SYMMETRICALLY DISPOSED ABOUT AN AXIS ON OPPOSITE SIDES OF A SUBSTANTIALLY TRIANGULAR SLOT FORMED IN SAID PLATE AND HAVING SYMMETRICALLY DISPOSED ABOUT SAID AXIS, CONFRONTING SURFACES, INCLUDING EACH OF SAID NOSE PIECES AND EDGES OF SAID SLOTS OF SAID PLATES, HAVING FIRST PORTIONS TO POSITIVELY LIMIT SEPARATING MOVEMENT OF SAID NOSE PIECES WITHIN TWO PERPENDICULAR PLANES INTERSECTING THE CENTER OF SAID BALL AND SOCKET MEANS AND ADAPTED TO LIMIT SUCH SEPARATING MOVEMENT SUFFICIENTLY TO MAINTAIN SAID BALL AND SOCKET MEANS IN SELF-CENTERING OPERATIVE ASSOCIATION FOR RESEATING UPON TENSIONING OF SAID ASSEMBLIES; SECOND PORTIONS OF SAID CONFRONTING SURFACES POSITIVELY LIMITING PIVOTAL MOVEMENT OF EACH OF SAID ASSEMBLIES ABOUT A PAIR OF PERPENDICULAR AXES INTERSECTING THE CENTER OF SAID BALL AND SOCKET MEANS AND LYING IN SAID PERPENDICULAR PLANES; EACH OF SAID ASSEMBLIES BEING PIVOTAL ABOUT BOTH SAID AXES TO MOVE A NOSE PIECE OF ONE OF SAID ASSEMBLIES INTO A CORNER OF THE SLOT OF THE OTHER OF SAID ASSEMBLIES, ONE OF THE ANGULARLY RELATED EDGES OF THE PLATE OF SAID ONE ASSEMBLY THEN PROVIDING CLEARANCE WITH THE CORNER OF SAID SLOT OF THE OTHER ASSEMBLY TO MOVE SAID FIRST PORTIONS OUT OF OPPOSING REGISTRATION TO PERMIT FURTHER SEPARATING MOVEMENT OF SAID NOSE PIECES SUFFICIENTLY TO DISPLACE SAID BALL AND SOCKET MEANS OUT OF SAID SELF-CENTERING OPERATIVE ASSOCIATION AND TO ALLOW ACCESS TO SUBSTANTIALLY ALL SURFACES OF SAID BALL AND SOCKET MEANS. 